Apple could be working on seamless unibody headphones for its iPod and iPhone, that won't retain any dirt.

That's according to Apple Insider, who discovered two patent applications detailing the headphones filed by Apple last year and published on 12 April.

In the first patent application, titled "Ultrasonically welded structures and methods for making the same", Apple describes headsets that include non-cable components such as jack, headphones, microphones and cables that interconnect the non-cable components as "abrupt and aesthetically displeasing."

Therefore, Apple wants to create "headsets with seamless non-cable components and cable components that seamlessly integrate with the non-cable components."

Apple's planned headphones will "appear to have been constructed as a seamless unibody structure."

"Plastic headphones typically include holes that permit the passage of soundwaves from the inside of the headphones to the outside of the headphones. The creation o these holes can result in remnants left in or around the holes that degrade the aesthetic and acoustic properties of the headphones. Therefore, what are needed are systems and methods for deburring curved plastic objects," Apple's patent application describes.

The patent explains that a headphone cap can be deburred and polished to ensure that no remnants remain in the holes or on any surface of the headphone.

Apple is also thought to be working on a significant update for its iTunes software.